Welcome to the W3C HTML Validation Service; a free service that checks documents like HTML and XHTML for conformance to W3C Recommendations and other standards.
These are the most recent major changes to this service. See “What’s New” for more details.
Alternatively, you can upload files from your computer to have them checked.
You can also check your Cascading Style Sheets using W3C's CSS Validation Service.
Gerald Oskoboiny